A typical mistake which many Adwords advertisers make is to have a single ad group with all the keywords. They end up showing the same ad for all the keywords, thereby losing the keyword-message match and getting a poor clickthrough rate.
You should have only related terms in one ad group and ads that relate to this group of keywords. A different set of keywords relating to another aspect of your product belong to another ad group with ads describing that particular aspect.
Thus a web design company should put all Flash related terms in one group with a relevant message and .NET related keywords in another group with a related message. This will result in instant improvement of the clickthrough rate.