Otherwise, we do primarily real-time notifications and mobile marketing.
And you're right about the website. This is the kind of feedback we don't otherwise get, so thanks! I'm also pretty terrible at making blog posts or throwing marketing materials into the ether. Much better when there's something tangible to respond to (which I suppose is analogous to your comment on imaginary "average customers"). But do impugn away if need be, though I'm enlivened by the warm reception so far.
The API was developed primarily around our own - and by extension, clients' - needs, which are more application and real-time notification oriented (I don't want to come off as spammy listing some of the use cases, but can do so if there's interest - some neat stuff there, IMO), rather than just focused on mobile marketing.
We do run our own SMPP binds, but for most developers we offer an HTTP API, which we use internally. And we're Rails guys, if that's meaningful. SMPP would be the way to deal with SMS gateways directly, so we're just as 'direct' as Clickatell, though the most direct way is working with the carriers on your own. You can listen to Fabrice Grinda talk about how much fun that is (http://www.venturevoice.com/2005/12/vv_show_21_fabrice_grind...). The next tier down are the aggregators (http://my.safaribooksonline.com/9780596515133/using_an_sms_a..., and a less charitable take here, http://www.mobilemarketingwatch.com/the-problem-with-sms-agg...), who abstract the carrier connections for you. Just below that are companies like ours. The differentiators at that level are pricing, live shortcodes, two-way messaging, APIs, and experience in building mobile apps. Plus dealing with carrier problems. Mobile messaging can be discouragingly complex and costly.
So our ideal client would be another startup or SMB that could benefit from having comparable binds to an aggregator, without the months of setup and at a fraction of the price. Basically, we'd like to be a company we wish had existed when we were getting started. You would have to do decent volume to make it worthwhile, so it's not for everyone. The nice thing about not going mass-market is that we can be a bit more flexible. For example, we don't cap the number of top-tier keywords we offer, so you can use them for A/B testing across, say, print ads in different newspapers. Or you can resell them to customers.
And yes, that's a Wufoo form... we have them set up on other sites, usually with a bit more attention paid to the CSS. We don't have to build forwarders and reporting tools - even a couple hours of dev time here and there add up, so we ruthlessly outsource non-core activities :)
Thanks for the upvotes! Cofounder here, thought I'd add a clickable link to what might interest you more: http://privatelabelsms.com/api
Looking at my account created 872 days ago, I'll take this as the impetus I need to actually participate.
Any questions on SMS or the mobile industry in general? I've seen a lot of confusion and misinformation on the topic, and regrettably I didn't make strides to correct it then.