Does hyphenation makes a difference?

[Stephen Edwards]

If you write 'four poster bed' and 'four-poster-bed' are they read the same by robots, or is one preferred? Is writing 'four_poster_bed' even better?

I am wondering whether this is making a difference to how my webpages are read, and so affecting ranking?

[viradian]

search engine spiders read hyphens as spaces...so if you type four-poster-bed, it is the same as four poster bed. If you type fourposterbed, then the search engines have trouble deciphering individual words. That's why many sites hypenate their URL.