The title tag is one of the most important factors, as far as the search engine optimization of your website’s pages are concerned. If the title tag of individual pages aren’t optimized well, it would be extremely difficult to rank for the keywords and phrases you are targeting.
For example: If you want to rank for “Best Hotels in London”, try to come up with meaningful and specific titles rather than generic titles e.g “ABC Hotels – Blog name”.
But what about separators in the Title Tag ? What should be the ideal separator when you are targeting multiple words and keyword phrases for the search engines. Should you use a dash (-), a comma (,), a pipe (|) or an underscore ( _ ) ?
Google Engineer Matt Cutts has a simple answer – use whatever you want to but avoid the Underscore at all costs.
When you use an underscore as a separator for words used in the Title tag, Google and other search engines would not consider the underscore as a separator. Instead, the search engines will consider the underscore as any Generic character.
Example: Let’s say you use this key phrase “A_B”, trying to target the words A and B and using underscore as an operator. In that case, the search bots will think that “A_B” is a single word and they won’t recognize the words “A” and “B” as independent keywords in the “Title” tag.
As Cutts says, “You may use spaces, dashes, pipes or commas – all of them are good separators for words used in the Title tag. Try to write a title which looks pretty and clean for users and any of these characters can act as a good separator. So whatever you think looks best for users or converts well can be used in the Title tag as a separator, they don’t have any effect as far as SEO is concerned. Using any of those characters as separators will work just fine. But do not use the underscore, it’s not recommended at all”
Related reading: When you should ignore the meta description tag
I would recommend using a combination of these separators, depending on the situation. For example, for the title of this blog post I will use all the three separators (comma, space and dash). This is because it is more human friendly and looks good in the SERP’s. I won’t bother much regarding which separator should be used, because they don’t have much SEO effect whatsoever.