It is important that you use the best settings possible when making a web video. This is crucial because when you upload yours to sites like YouTube they will then compress it using their own codec. If you dont use the right settings initially then of course the video people will view online wont look the same as the original that you uploaded.
The first to do is make yours into an MP4 file with H.264 codec. The reason for using an MP4 file is that the quality of the video being seen by others is much better. Also it is a file format that most video sharing sites like YouTube like.
The second thing you should do is make sure that you produce it in standard definition so make it 640 pixels wide by 480 pixels high. Of course you can make it in HD (high definition) if you wish but again make sure that it is 1280 pixels wide by 720 pixels high.