The only time I use the MLC search is when searching specific MATLAB functions to remind myself of the options and such for functions I already know about. Otherwise a web search just makes more sense, casts a wider net while still getting the relevant information within the first 5 hits 99% of the time.

Web searches are generally faster and more useful as far as I'm concerned. I'm often looking for information which might be on the forum or in documentation. There isn't a good way to search both from within the site. Yes, the general site-wide search (like the one on this page) works, but it's incredibly slow for me. Web searches also pull up relevant stuff on the FEX, GitHub, StackExchange, etc. That said, it does pick up plenty of trash too.

Can you explain the difference between #2 and 3? MATLAB Central has a search field that says "Search MathWorks.com". However if you're in Answers it says "Search Answers", and if you're in File Exchange it will say "Search File Exchange". All 3 of those search only the Mathworks site, not the whole internet like Google would (though you can use "site" keyword to limit Google to just a specific site). However the MATLAB Central search searches the whole of Mathworks.com, rather than just specific parts (Answers or File Exchange) of MATLAB Central. So I'm a little unclear as to exactly what and where 2 and 3 refer to.