?What/.? addition in front of each post title of my website.

Disable each plugin one at a time to see if the issue goes away. You should be able to identify which plugin is causing the issue. From there, you should be able to try and get support from the plugin author or from the forum.

Can you switch to Twenty Thirteen theme and see if you still get that what/ . before your post title?

I disabled all this pluging,and still the same problem
– Broken Link Checker 1.9.1
– Google Analyticator 6.4.5
– Google sitemap plugin 2.8.3
– Sociable 4.3.4.1

I switch for tenty Thirtheen theme…without any change with my problem ??

And I tried a new post…with the same problem

So can you post a link to an example of the issue on your site with the default theme activated and plugins deactived so we could see?

https://www.marathons-canada.com

What version of WordPress are you using? Sucuri says that you need an upgrade. Also you are using the Running And Jogging Wp Theme which is not the default them and you have some plugins activated.

https://sitecheck.sucuri.net/results/www.marathons-canada.com/

3.7.1
I tried with Twenty Thirteen theme with the same results.

And I desactivate all pulgin activated since the problem appear;

The only plugin already activated are this:
Akismet
Official StatCounter Plugin
Multi rating

But the site work properly with that plugns…

I just install the 3.8 version… without change

The problem was occur with the plugin Multi rating… I dont know why the problem occur after few days… but with that plugin desactivate…all is OK ??