We get a lot of requests from other companies who want to integrate their services into Posterous. 

When you're running a lean, focused startup, it's hard to stop working on your product to even entertain the idea of integrating with someone else. If done right, it can be a win for both companies. But more often than not, it's just a huge distraction. We've found that integrating with other companies only works if:

• There is a clear win for both companies 
• The integration points are simple and clearly defined 
• Both companies are willing to set a deadline and focus on the integration 

One major roadblock that we often face has to do with accounts. People come to us and want us to integrate their service, but then want our users to sign up with them. I'm sorry, but other than rare exceptions (Google Analytics), this isn't going to happen. It destroys the experience.

I'm not going to add third party integration that takes my users off to another site. We want all of our features to be available to everyone, without requiring other setup first.

Here are some of the integration success stories within Posterous:

Services that don't require an account

• You don't need an account to post to Posterous. It uses your email address as identification.
• You don't need an account to post using PicPosterous on the iPhone. Just launch the app and take a photo. It uses your phone's UDID for identification.
• Posterous embeds documents using Scribd's javascript API, and our users don't need a Scribd account.
• We offer Retweet buttons through Backtype, and Like buttons through Facebook, an all Posterous sites without an account.
• Posterous auto expands URLs using OEmbed and other standards.

Using someone else's authentication system

• The brilliance of TwitPic and why it's so successful is it uses your Twitter login for authentication. They don't require you to create a different account on their site. (Were they the first to do this?)
• When we developed our API as a TwitPic alternative, we too based it on Twitter authentication. Just a year later, we're integrated in almost every Twitter client out there. This wouldn't have happened if we required users to have a Posterous login.
• We made our API a 100% drop in replacement to TwitPic, matching the calls and responses perfectly. We wanted to make it as painless as possible for clients to add us.

When all else fails, go the extra mile to make it easy

• We recently released integration with Typekit. This does require users to first sign up at typekit.com but we made it as painless as possible.
• From Posterous, users are redirected to a Typekit.com landing page designed for Posterous users, so it's clear why they were redirected.
• After signing up, users are redirected back to Posterous and the Typekit ID is added to their account, no copy/paste needed.

Major props to the Typekit guys. They did everything in their power to make the integration totally painless for Posterous users. It was awesome working with them and we hope to do more together. And credit to Singy for actually doing the integration.

If you want another company to use your services, then you need to make it easy. Scribd wants Posterous to use their embeds, so they have a great API. Posterous wants to be in Twitter clients so we made an API that matches other APIs.

Don't think that another company is going to bend over backwards to add your services. You should go out of your way to make it easy for them, and then be grateful. And to that, I thank everyone who is using the Posterous API today to make our service even better.