I'm having fun looking at the many "spoiler" photos of Merlin 4 shooting at Pierrefonds Castle in France. Some really good ones, but not really spoilers. Knights on horseback, some practice fighting, Gwen in a lovely new dress, no longer a servant type garment, and lots of photos of Rupert Young/Sir Leon having a great time. There are also snippets of information about new characters.
Some fans went too far and kept trying to get through security. They found a script and photographed some pages. That's really going too far. Dishonourable behaviour. The pages are on the Internet but I won't read them.
One of the qualities of Merlin that I like is the relative innocence. No graphic violence and sex, which makes a refreshing change. (That is not to say I don't enjoy series with those elements.) I avoid fanfic and sites with slash pairings, which would spoil the series for me. An example of the innocence is Arthur wanting to marry Guinevere rather than making her his mistress, which would be realistic.
It's enjoyable to see photos while waiting for the series to come out, sometime between September and November. Then I'll have to wait a couple of months for the DVDs. But, with the year running away with itself as it is, that's not long.