It used to be that I judged a new social tool, service or application purely on intrinsic qualities such as functionality, usability, design or utility. In an increasingly competitive social media landscape, where even niches are getting crowded, what is it that makes one tool stand out above the others?

Ecosystem. Plain and simple. What kind of API does the tool provide? How vibrant is the developer community? What other tools and services are building up around it?

Twitter, for example, has a really vibrant ecosystem, full of tools that allow you to post pictures, track compressed links, analyse statistics, manage your accounts, send Tweets longer than 140 characters. The ecosystem is so vibrant that a service devoted just to cataloguing it has sprung up: OneForty.com.

Wordpress is another tool with a fabulous ecosystem, not just in terms of plug-ins and themes, but also in terms of developers. I’ve never had a problem finding WP developers to help me out when I need a hand wrangling the finer points of WP admin.

The Delicious ecosystem, on the other hand, appears to be moribund. The Firefox add-on that I used to rely on, Delicious Complete, is now defunct (does not function in FF3) and I can’t find an alternative that allows me to manage multiple accounts. There are a handful of dedicated add-ons for Firefox, but beyond that the wider developer community is either invisible or just doesn’t exist. New tools, like Instapaper, that could tie in with Delicious don’t. That’s a real shame because Delicious is one of my favourite tools, but it simply isn’t that easy to embed it in my working processes.

I know that there may be some very good reasons why some tools have better ecosystems than others, but as I’m not a developer and have never looked at the barriers to entry for working with these different tools, I can’t speak to that side of the debate.

But ecosystem is very important to users not just in deciding which tools to use, but whether to be loyal. The cost of switching from Twitter or WordPress to a competitor is quite high. It’s not just a matter of swapping one service for another, but of having to start again with the community, whether that’s moving your own social network over or finding new people to worth with on the new platform. The cost of moving from Delicious, however, would be relatively low. If someone offered a better service with better tools and even a small ecosystem that showed promise, I wouldn’t hesitate to migrate my data.