When you have a lot of tags you can can group similar tags in groups, a short exemple:

Tools Tags: 1Dreamweaver, 1Flash, 1MySQL
Language tags: 2PHP, 2HTML, 2CSS
Weather Tags: 3Hot, 3Rain

So, when you typing the tags all you need is to select the group, typing 1 for example, and the tags will become a list you can choice.