Where the standard Tweet button gives you little control over the button’s appearance, functionality or call-to-action (you can Tweet, Tweet or Tweet) you have virtually unlimited options when encouraging users to follow you on Twitter.
This is because the following action takes place on Twitter itself, rather than on your website: you’re essentially encouraging a user to click on a link. As such, there’s more optimization and testing opportunities.
Your call-to-action can take the form of a text link, a linked graphic or both. This gives you the opportunity to create and test any number of calls-to-action until you uncover the formula that delivers the highest number of followers.
Best practices for other calls-to-action can be called upon here: the use of action verbs, brief but compelling text that provides an incentive to click the button, and so on.
Factors to consider here are the closeness to the Tweet button, the positioning of other network join buttons (especially your Facebook call-to-action) and the relative effectiveness (or ineffectiveness) of a call-to-action to follow in a place like the sidebar.
A stream of your recent tweets may provide an additional incentive for visitors to follow you if, of course, they like what they see. This technique will obviously work best if you have a very active Twitter account that displays a high level of interaction.
Direct Following With Twitter
It is technically possible to have a button that allows users to follow you without leaving your site.
To accomplish this with any degree of customization entails creating and registering an @Anywhere application, so is really only suitable for those with development skills.
Tweetmeme also provides a follow button, but there are few customization options available. These options are worth exploring if you have the skills to implement them and want to try and decrease fallouts in the following process, but users are fairly well-accustomed to initiating a follow on the Twitter account page itself.
In any case the official Twitter button itself provides a mechanism for following without leaving your website. Any visitors that successfully complete a Tweet from your webpage are subsequently presented with the option of following one or two Twitter accounts.
This, in itself, is another compelling reason to use the official Tweet button, as this functionality is built in.
That you can suggest two Twitter accounts to follow in the pop-up is particularly useful for content sites, where often both the author of a post or article and the domain itself have Twitter profiles (accounts the visitor is already following do not appear).
A line of text can optionally be inserted above the profile block, providing at least a nominal opportunity to create and test a call-to-action.