Question: I have a website hosted under a subdomain for testing purposes and have tried to validate the html and css using w3 validator and jigsaw. Depending on the URL I use - <http://alt.example.com> (9 frameset type errors 4.01 Strict, CSS3 pass) OR <http://www.example.com/alt> (passes HTML5 / fails CSS3 183 errors, mostly vendor extensions). Why do the links validate differently and which one should I be concerned with? Any ideas on how to go about fixing them would be great. 

Mystique Theme,
Mystique-Child Theme (with its own style.css using @import url for core.css),
WordPress 3.4

Answer: 
The answer depends on how many such requests will happen and how many concurrently in your web app ? Connection pooling is usually a better idea if you expect your web app to be busy with 100s or even 1000s of user concurrently logged in. If you are only doing this as a side project and expect less than few hundred users, you can probably get away without pooling.
I think connection pooling is the best thing to do if this application is to serve multiple clients and concurrently.