Avoid words which have a lot to do with the Net in general.When a user
searches for one of these words they get a huge number of results and
yours is likely to be way down the list.
The purpose of keywords is to target words that will bring people to your
site as opposed to other people's. Since nearly every site on the Net is to
do with 'web' or 'internet' or 'services', using these words to target your
audience is pretty pointless.
Most of the robot-driven engines actively ignore common words like this.