Site search

[ercatli]

I would like to set up a simple site search on a website. Google has one, but it requires me to accept ads, which I don't want to do. There are scores of other free site searches available, and I'm having trouble getting my head around them all and getting an initial understanding. Can anyone offer me any advice please on the following questions:

1. For a relatively low traffic site, can you recommend a good site search?

2. How do they work? Specifically, do some site searches work entirely on the site server, while others require sending information back to the search engine site?

3. What language are they written in?

4. Are there any well known traps for young players, or things I should know before I start to download anything?

Thanks. Getting a little advice would help me get started without wasting a lot of time.