What makes web services sticky?

The number of technology startups is quite staggering. This, of course, is a result of virtually no barriers to entry and a relatively low production cost that’s associated with tech startups (namely dot-com businesses and services). But what separates those popular (mainstream) startup services from the “soon forgotten” ones?
It’s a matter of stickiness…But what makes something sticky?
There are a number of factors that contribute to the “stickiness,” or staying power of an online service. The first lies in the power of early entrants. Not surprisingly, it helps to be the first to accomplish something new. Twitter is a fine example of an online service who is feeling this competitive edge first-hand. Launched in 2006, Twitter has seen tremendous adoption from the online community, legitimizing the micro-blogging platform it has essentially invented. Since its launch, there have been many imitators, but none have seemed to garner the attention that Twitter has been able to obtain. Digg falls into this category as well. After popularizing the social-bookmarking and content-sharing platform, Digg has built up a dedicated userbase. Many imitators have launched similar style websites, but have been unsuccessful in gaining the same following. Being first often makes you sticky…initially atleast.
The second “stickiness” factor is execution. If you aren’t fortunate enough to be the first to enter the game, you had better execute. Google exemplified proper execution when they created a better search engine than than their competitors in the late 90s. Facebook was not the first social network, but it was Facebook’s execution that ultimately made it the #1 social network that it is today. It goes without saying, stickiness clings to the services that deliver.
The third factor is simplicity. There is no reason for web services today not to be super-intuitive. Internet users today expect to be up-and-running in a matter of minutes. What is the reason that Myspace has taken the backseat to Facebook in terms of total unique visitors? In my opinion, it has a lot to do with simplicity and ease-of-use. Facebook absolutley crushes Myspace when it comes to social networking because of the differences in design and functionality. Simplicity is a huge stickiness factor.
The fourth factor is of stickiness is not entirely controllable, but very important; that is, the network effect. Today’s web 2.0 applications are only sticky if they are able to attract a huge network of users. This network effect, which has been debated and analyzed time and time again may be the most important stickiness factor of them all. If the users aren’t there, the service will likely falter. A service needs an active community to remain sticky.
Can you think of any other factors that contribute to a web services stickiness?