I cast a Swedish expat vote (and it certainly wasn't for SD) 
I think the more profound impact on Swedish politics is how anti-immigration sentiment has moved into the political mainstream. Two years ago, it was taboo to suggest hundreds of thousands of people immigrating in one year could be anything other than good. Now, the consensus has shifted (and remember Sweden is a country of consensus), so it's acceptable to talk about immigration and, sadly, to be much more racist in mainstream politics.
Because it was seen as beyond the pale to question immigration, there wasn't a healthy debate when we needed to have one – and now we're stuck with the Swedish Democrats and the sort of political climate Denmark and Norway have had. This has a lot to do with the way Sweden works – the consensus – so I wouldn't necessarily see it as a harbinger for other countries.
Now, excuse me while I weep at the SD statistics in my hometown... although here's an interesting thing for you. One can see the breakdown by locality, so down to less than 1000 votes.
The town voted the social democrats top, both the wealthier and the poorer parts (where most immigrants live - remember the segregated housing market), with SD coming in second or third. The wealthier the area, the more voted for the moderates instead of SD.
In the surrounding villages, any industrial clusters voted social democrats while SD comes in on top elsewhere. This would be where there aren't that many immigrants...