This is one for the B2B companies, business dynamics in B2B vary greatly from B2C, but you still need an excellent tool to stay in touch with past and possible clients, unlike B2C, the approach has to be more personalized,so at TITOMA we use Buzzstream to accomplish this.
What do we like about Buzzstream?
You can easily access every single email you've sent to a particular person.
You can do more than just linking an email address to a name; you can also link all of their social media profiles, websites, phone numbers, and more.
There are plenty of autofill tag options to personalize every email batch.
You can set a different status for each connection: Replied, Interested, Accepted, etc...
You can create different segments in your database.
They have a tool to discover influencers in your niche, and they make it easy to add it to your database.
They have a Chrome extension that makes it easy to add people and any relevant links or other information to your database without leaving the site you're on.
What we don't like?
Linked in is the best social media to stay in touch with B2B leads, as of right now, there's not much you can do when it comes to integration between Buzzstream and LI. You can though track twitter conversations.
Buzzstream advertises itself as a PR tool, well, we've found that it satisfies all of our B2B email needs, it gives us a lot of control on how personalized we want the emails to be.