This is where services can afford to compete most aggressively: by allowing customers more freedom of movement with their data, even if it seems counterintuitive at first to let them leave. "Vendors should sell their functionality, not create lock-in with technology," says Hamilton, noting that the general movement in the industry is toward open standards of one kind or another.
Reichman, however, disagrees. "The most likely [scenario] is one vendor's proprietary structure becoming a de-facto standard that other vendors follow," he says.
Watch for warning signs
Is it possible to tell ahead of time if a service's plug is about to be pulled? Sometimes the best places to look for signs of that happening are not on the service itself.
The ArchiveTeam Web site maintains a list of sites that are in danger of being shut down or are already dying. If you use a site listed there (under the heading "Watchlist"), it's probably a good time to think about taking your data elsewhere or, at the very least, backing it up somewhere solid.
Reichman advises looking at the company's numbers. "You can't always discover that a potential vendor has financial problems, but some issues can be uncovered with a bit of due diligence in financial statements, if available, or funding history and any news stories about the vendor," he says. "Rumors of impending acquisitions or divestitures, layoffs or strategy shifts are all signals that there may be trouble looming."
Both Reichman and Hamilton say there may be few outward warning signs, even financial ones. "Companies in fiscal trouble typically don't pre-announce that kind of trouble," notes Hamilton. "You need to be proactive. If they're a public company, you can see their financials. If not, you should still watch to see if they're in the news. If you have questions about their viability, don't use them in the first place."
That said, again, it's hard to say no to a particular service if job requirements or peer pressure require you to do so, especially without viable alternatives. For a time it was difficult to spurn Facebook, for instance, despite its lack of data portability and questionable privacy practices -- everyone used it. Now that wall of dominance may be crumbling a bit with the appearance of Google+ and the quiet success of LinkedIn.
Other warning signs include:
Declining quality of service. An ongoing, chronic disintegration of the service -- "increasing service disruptions or performance issues", as Hamilton puts it -- is a major red flag. He adds to that, "a general lack of responsiveness to calls or emails."