DiseaseSymptoms.org presents a design that seems well fit to its topic with a predominantly red color scheme, a well known symmetrical medicine logo and a medical red cross symbol next to a 3D rendering of the word "Medical". Other than that the site is fairly light on bells and whistles and remains rather simple.
A few possible improvements come to mind on just the homepage. A search box for searching the site is missing. Sometimes the upper link ad unit displays a search box which may lure people to it, but it doesn't search the site. Speaking of the link ad, it might be better positioned within the bar holding the "home" link as there appears to be enough horizontal space for it and this would perhaps slightly reduce the sense of clutter already contributed to by the square ads. Also, the advertising block could look better if the ad within it were centered.
Article pages look good, I like the red square style of bullet points, but some articles are a little disrupted when two square ads end up positioned too close to each other. There's one issue with hovering of the "share and enjoy" buttons that I wasn't sure how to describe so I made a screenshot (picture's worth many words):

Finally, I believe it might be worth trying to rearrange the layout of the site to something more efficient. Instead of using three columns it seems like it could easily make due with only two. The advertising block on the right could be moved to the bottom of the left column and the content column could be allowed to expand over the area currently occupied by the right one. Of course it could go the other way around leaving the right column and moving the left stuff to it as well.
Design Rating: 7/10
Focus:
"If its a symptom we will tell you", says the slogan of Disease Symptoms dot org. I suppose that means that if you feel something and wonder it may be a symptom of a disease this site will tell you, which sounds good. In any case the focus is obvious and the content aligns with it consistently. Hypochondriacs beware. ;)
Focus Rating: 10/10
Content:
This site offers over 50 articles covering the definitions of subject diseases, their symptoms, causes and treatment, often using bullet points which make the information easier to read. They're overall fairly brief and so might not necessarily be too comprehensive, but they probably don't need to be for most people. They cover the symptoms, which is what the site's title and slogan promise, and offer additional basic information.
Content Rating: 10/10
A decent disease symptoms database covering over 50 diseases along with causes and treatment information. Some further design polish couldn't hurt it.
MedicalSymptomsGuide.com looks somewhat like a standard blog, tightly knit and with a pleasant color scheme, but somewhat burdened with ads. It might in fact be a little too tight as it could use a little bit more margin left and right to the main content as well as between the title area and the category and comments area. It might be worth considering making the width of the site fit 1024x resolution rather than 800x given that only a low single percentage of screens use 800x resolution nowadays. A larger width could allow for larger margins making the site's design look fresher and more spacious.
The main menu styling with only a link to "home" makes the menu blend in too much into the background making the tab on which the link lays almost indistinguishable. Perhaps the background color of the tab could be darkened a bit, using some sort of bluish gray so it is more distinct.
Another thing that is noticeable is that there are no listings of categories yet there is a listing of recent entries. Since five of these recent entries is already shown on the homepage it seems like it is a less optimal choice than putting the listing of categories instead. Of course, alternatively both could be present, but categories should probably have a priority. I would say both should also have a priority over ads as well, but even if the ad at the top of the sidebar was kept, perhaps a vertical banner or a small square would suffice rather than skyscraper?
In any case design is decent and does the job. These suggestions may close some of the issues, but it wont make it overly impressive. Perhaps the nicest thing of all, aside from the color scheme, is the golden plus/cross logo.
Design Rating: 8/10
Focus:
Relatively long name spells out the focus of the site as a medical symptoms guide in addition to the slogan, "your guide to medical symptoms" which really leave no place for ambiguity whatsoever. Content follows this purpose closely with "symptoms" in all of their titles. Again not much more to add or complain about here. An about page is a classic suggestion, but it's not a real necessity.
Focus Rating: 10/10
Content:
Medical Symptoms Guide currently contains over 100 relevant articles on symptoms usually split into sections corresponding to signs, diagnosis, treatment and prevention. As usual with this author articles are serious, professional and to the point, bound to be useful. This is raw, no fluff, information.
Content Rating: 10/10
Design might not be overly impressive, but it is decent and those in need probably wont care too much because the content once again wins the day. It is a quite a valuable resource of medical symptoms.
WhatPain.com looks and feels like a health site, but it's hard to explain why. The two yummy green pluses (or crosses) in the logo and an overall bright, but gentle color scheme probably have much to do with it. The color scheme is quite consistent, basically following the colors of the logo itself (a practice I tend to use in my designs). Alternating blue and red titles matching the blue and red of the site title and green background of category titles matching the green of those two pluses. Overall it really feels quite elegant and sterile.
The sidebar blocks have a slightly 3D feeling to them thanks to a nice play of border colors giving the site a more pleasant feel. The content area at first sight seems somewhat misaligned, as if the recent articles block could have been better put as part of the sidebar. However the borders between article teasers somewhat fixes this impression by making the teasers and the recent articles a part of the same centered structure. Still, it may be worth trying an alternative by putting recent articles in the sidebar and extending article teasers to the full width of the main column. At least this would remove the single small disadvantage of the current style, the white space below the recent articles listing.
The category view is quite flawless with one minor exception. The pager almost collides with the last teaser. It could use more top and bottom margin. While we're at it the borders of the pager could use a lighter black (or gray) color to better fit the rest of the site. Current black border seems a little too strong given the context.
Article view is quite good with the exception of cases where article is too short to efficiently fit the two square ads. I would also, as usual, suggest using heading tags instead of strong tags for article section titles.
Design Rating: 9/10
Focus:
WhatPain as the site's name can sound as both a question and an exclamation: What Pain! Either way it hints at the site's purpose quite well as just a quick glance over titles on the homepage reveals their topic, that being various types of pain one might feel. At this point one is likely to assume the site describes symptoms and what could those symptoms indicate. However, it could still use an about page just to make this more explicit.
As far as the focus of site's content on the subject matter is concerned though there can be no complaints. The site is called What Pain and articles are all about pain.
Focus Rating: 10/10
Content:
Over 80 articles about specific kinds of pain and related causes, symptoms, diagnosis and relief can hardly go wrong. There are a couple of posts which I found laying around which are just demo posts though and were probably overlooked. One is in the Venerical Disease category and another among Viral Infections. All articles seem to follow an outline that involves an introduction and then a description of symptoms, causes, diagnosis and relief which is good for consistency and gives an additional air of professionalism, albeit they aren't always presented in the same order. Articles are reasonably brief, serious and to the point. An obvious additional benefit is that it is an one-stop resource with regards to discovering what a particular pain one may feel might mean.
Content Rating: 10/10
WhatPain is an excellent resource for discovering additional information about particular pains with a soothing look and feel. The few issues that were identified are fairly minor and only minimally disrupt the overall experience.