There are hundreds of witnesses at the moment. However only less than 100 are active. Every witness has a different level of involvement on the Steem platform. They range from developers, programmers, techies, engineers, to regular people, from all over the world. Each contributes to the community in their own ways. Witnesses usually post in the #witness-category. They introduce themselves by describing their projects and how they envision their contribution to Steem. Also, they write about their server and activities updates. The contributions are diverse. They can be technical, community-driven, artistic, etc. So whatever sings to your heart, vote for it.
In order to support the deeds of your chosen witnesses, vote for them. But deeds aren't the only important factor. In fact, witnesses are expected to run a stable and reliable server to avoid missing blocks and keep the network healthy.
Here are few clarifications about witness voting:
Here are the steps for voting.
If your witness is not in the top 50, scroll to the bottom of the page. You will see the VOTE box. Enter your witness name (without the @) and press VOTE once.
Once voted, their name will appear under the VOTE box, with a blue chevron next to it. This means they're voted for. Many users click that blue chevron, but this will UNVOTE them. So don't press it, unless you're shuffling votes as I explained earlier.
NOTE: Sometimes people cast their vote and consecutively unvote! So, after you finish voting, refresh the page (press F5) and make sure your votes are locked in.
Some users prefer not to trouble themselves with witness researching and voting. In that case, you can choose a proxy that will vote for witnesses for you. By doing so, you will RESET your current witness selection and remove all your previous votes.
Voting for witnesses is as important as writing posts. Supporting your witnesses helps motivate them to continue providing their knowledge and contribution to the Steem community by hosting the blockchain