This is not a good stock to invest in. The technology in this space is highly commoditized. The only real differentiation is through services and relationships. They have a decent enough product, but the handwriting is on the wall for the email space and they know it. that's why they keep saying they are geting into social and banner ads...but there is no real leverage between those different channels. Email will always be around, but the volumes aren't going to grow really and that's the only way Responsys can really grow their customer base.
It's not a bad company if they just wanted to make it a nice smooth ride, but the only reason they had to go public was to monetize the early investments. Nothing wrong with that but don't think you're investing into a growth story waiting to happen.
There is no apparent sales or growth strategy either beyond continuing to talk about these other channels that they say their customers are excited about but they never seem to sign up for.
They'll probably be bought out by an agency or something, but the underlying technology is pretty much the same and won't command any kind of serious premium.