I will interject that there are search engines that would not "have this problem" and they all suck for any real searching. Lotus Notes comes to mind, the search engine is literally like being punished!
The problem with allowing so few characters is that your search becomes so ambiguous that the hits returned are pretty much useless. It would be like asking for 1/3 of the posts on the site, only without any organization, only ordered by the post date.
There are Natural language search engines, most of which really suck badly. Our Knowledge Base system where I work uses a natural language search engine and it is almost impossible to find some of the articles because those who wrote them have no clue how to write for the engine.
I happen to be intimately familiar with that one, as I am a reviewer for our knowledge base, after it was discovered that I was the best author in our group, lol. Unfortunately, that means that I no longer write articles
