I resisted this for about a week, but having been in the startup/small company scene for a while some years ago, I had to speak up. Mark Suster wrote this piece about how job-hoppers are bad employees, and it's stirred up a lot of dust.
Now, the part that gets my blood boiling is the part about how (supposedly) job-hoppers have shown they are disloyal. And how that is not what you want in a startup employee.
I call bullshit. This is a blatantly pro-management position that expects the employee to be a chattel to the company.
Loyalty means that you will sacrifice some of your benefit to benefit them. For a company, this means giving raises without them asking, when you can. It means keeping them on payroll when there is cash in the company instead of having a layoff because it would make the shareholders happier. It means adjusting their equity to make the IPO sweeter for them.
For a startup that's cash-poor, you've problem in that you can't pay better, and you don't have the buffer cash, or the clout to give them a better benefits package. So what do you do? One thing you don't do is claim that working for you is a privilege. Unless you are betting your entire future on the company, they're taking nearly as big a risk as you working for the startup. If the company fails (as startups are wont to do), will you have to declare backruptcy, sell your house, move in with the in-laws? Because they might have to, if the job market is bad. I had one 3-job year, courtesy of 2 bad sets of management (acquisition of a debt-ridden "asset" in one case, and a VP that got distracted by a new piece of technology when he was needed to justify a budget), and it was not a fun time.
Here and here are some other takes on my side of the issue.