If the site is not in index of WebArchive -> error in main page (seo-widget):
Warning: file_get_contents(http://wayback.archive.org/web/*/[domain.tld]): failed to open stream: HTTP request failed! HTTP/1.1 404 Not Found in /[path]/core/Http.php on line 417
Backtrace -->
#0 Piwik_ErrorHandler(...) called at [:]
#1 file_get_contents(...) called at [[path]/core/Http.php:417]
#2 Piwik_Http::sendHttpRequestBy(...) called at [[path]/core/Http.php:79]
#3 Piwik_Http::sendHttpRequest(...) called at [[path]/plugins/SEO/RankChecker.php:58]
#4 Piwik_SEO_RankChecker->getPage(...) called at [[path]/plugins/SEO/RankChecker.php:183]
#5 Piwik_SEO_RankChecker->_getAgeArchiveOrg(...) called at [[path]/plugins/SEO/RankChecker.php:145]
#6 Piwik_SEO_RankChecker->getAge(...) called at [[path]/plugins/SEO/API.php:72]
#7 Piwik_SEO_API->getRank(...) called at [[path]/plugins/SEO/Controller.php:34]
#8 Piwik_SEO_Controller->getRank(...) called at [:]
#9 call_user_func_array(...) called at [[path]/core/FrontController.php:138]
#10 Piwik_FrontController->dispatch(...) called at [[path]/index.php:53]
[path] and [domain.tld] - modified by me
Piwik 1.10-b3 from git