Ovt shows how many times a keyword (or group of keywords in no particular order) is searched on the search engines Ovt tracks.
To answer the 3rd post, ovt bid tool shows what advertisers are bidding on specific keywords or group of keywords. Typically, they pay more for more frequently searched terms that their target market is looking for.
Generally, the value of the suggestion tool is that is shows the popularity of a term and having a domain with that specific term (alone, if possible) and .com gives you some indication of how much type-in traffic you'll get. I usually estimate 5% - 10% of the overture number. (Eg, let's say "whole wheat" gets 15,000 Ovt results I would expect wholewheat.com to get around 450 type-ins a month - that's just my working math based on my exp.)