I would think neither would make a difference except for preference. Search engines are looking at word boundries (programming term) when parsing a string and would not recognize these characters as either a word nor a part of an HTML tag and likely will ignore them completely. From an SEO perspective, they would likely be totally ignored.
If it’s only colon vs. pipe: Use the pipe.
1. The colon might (more) often be part of the page title.
It might be confusing to have two colons. Example for an article called "Top 10: Songs":
Example.com: Top 10: Songs
It seems as if "Top 10" would be some kind of second-level category here.
2. The site title should come after the page title. The colon ...
Generally speaking, "hyphen" is prefered over "underscore" - I never had anyone use "periods" before, but for the sake of this question, I recommend hyphens over periods. It is more a readability thing. However, it will neither make or break your site. The only thing that matters when it comes to SEO is that you have a product/service that is needed by ...
You may use any sign as separator, but you should always keep the readability in view. Suffering readability will for sure suffer your SERP CTR - and this would be too bad, to get an impression but to loose the click.
Google will recognize your keywords anyway - it will do it based on words placed befor and after words, which are weirdly separated, like in ...
You can use the form you want and if Google wants to rewrite your <title> tag, he will do it. For your information, if your website use a specific brand, Google tends to rewrites <title> tag like this:
Your brand: your webpage description
Here's the information from Google on that:
Brand your titles, but concisely. The title of your site’s ...
First of all, let me open by saying I personally answered your last question and my proposal was option A. Since I stated my thoughts regarding option A, I will just say why options B and C are no good.
Option B uses comma as delimiters for range. Comma is an unsafe character, meaning it will be encoded to %2C in your url and will generally seem like ...
Couple of points to add:
1) Underscores are a JOIN operator
2) Dashes are SEPARATOR
3) Periods are for SUBDOMAINS
This is old programming language standards. So all of that is to say, dashes are the way to go. If you use periods your URL will not likely get parsed correctly.
Check out the "double-click highlight_test," or was it, "double_click_highlight....
Personally, If I needed to use an operator other than a hyphen '-' I would use an underscore because it seems cleaner and is often used for variables when writing code.
In your comments you said you're needing the extra operator to perform a search using the words in the URL. If this is the case I would probably use the plus '+' symbol. Many websites ...
Where did you get the idea that | does subcategories? In search I understand that it is an undocumented replacement for the word "or". Regardless of it's meaning in search syntax, its semantics in titles is likely to be different.
Google ignores most punctuation in web pages and that usually happens with pipes in titles as well.
In short, it is fine ...
The rule of thumb for "SEO friendly URLs" is to create URLs that convey their content in a meaningful and easy to understand way to a human user. An approach I like is facetName=facetValue (so no facetIDs or facetCodes that the user can not interpret).
Since your ...
Space delimitation is fine. And while the keywords meta tag is no longer useful in Google, Yahoo, or other major search engines in the Western world, some Chinese search engines still utilize the keywords meta tag.