netmeg - 12:11 am on Apr 14, 2013 (gmt 0)
I've done both, and there are definitely pluses and minuses either way. It's never a good idea to have all your eggs in one basket, but on the other hand, maintaining multiple sites (and keeping them high quality) is a challenge, particularly if it's only yourself or a small team doing it. My decision on when to branch out is usually based on what's best for the users - I'll add to an existing site if I think it makes sense, but a lot of my sites are geo targeted to specific states, and those it makes more sense to keep separate, if only because it removes a layer of clicks to get to the right content. So, as with everything... it depends. If your additional content would enhance your current users' experience, add it to that site. If it can stand on its own, then make a new site.