Is Switching Jobs Too Often a Bad Thing?
Career Hot Potato asks: "I've been out of school for little more than a year and I have only good things to say about the job market. So far, there doesn't seem to be any lack of demand for a good .NET developer. I've got to admit, though, I feel a little disloyal at this point. Several great job offers have come my way and I've taken them. My resume is starting to make me look a bit restless and it worries me. Until now I've just chalked it up to 'I'm just settling in,' but now another opportunity has been dropped into my lap. Would I be digging my own grave by taking this job? It'd be my fourth job in 16 months but each offered a promotion and a 30% to 40% raise. I know better than to put a price on job satisfaction but I'm pretty certain I'd be happy there. Is being branded as a 'hot potato' enough to keep you from switching? What's your price on this stigma?"
Those are all things you do not want your interviewer to think.
Also, depending on how your new employer found you, it may have been a very, very expensive process. A lot of staffing/head hunter companies are locking companies into contracts, e.g., you will pay us for 6 months regardless of how long the employee works. So if you leave at 4 months, you're really, really screwing the company (out of work and out of (tens) thousands of dollars depending on your pay rate). Loyal or not, that will make ensuring those references are good ones more difficult over time.
With large increases without changing industries or job roles (i.e. .NET developer) across several jobs in a short time I'd suspect OP is not negotiating hard enough.
If other companies can afford to swoop in with a raise like that, you didn't get what you should have out of the company that currently employs you when you took that job in the first place.
If you want to switch, go ahead, but spend a lot of time getting the most you can out of them and then get some negotiating skills under your belt (there's books for that, don't read them at work).
Better yet, just negotiate a higher pay rate within the job you have... you have good evidence the going rate is higher.