Please, check the default keywords of XCL:
<meta name="keywords" content="news, technology, headlines, xoops, xoop, cube, xoopscube, nuke, myphpnuke, myphp-nuke, phpnuke, SE, geek, geeks, hacker, hackers, linux, software, download, downloads, free, community, mp3, forum, forums, bulletin, board, boards, bbs, php, survey, poll, polls, kernel, comment, comments, portal, odp, open, source, opensource, FreeSoftware, gnu, gpl, license, Unix, *nix, mysql, sql, database, databases, web site, weblog, guru, module, modules, theme, themes, cms, content management" />
These words are extremely anachronistic, and are not related to most of websites created witn XOOPS Cube and all XCL users may be penalized if considered "Keyword stuffing".
From Google: "Keyword stuffing" is the practice of loading a webpage with keywords in an attempt to manipulate a site's ranking in Google's search results. Filling pages with keywords results in a negative user experience, and can harm your site's ranking. Focus on creating useful, information-rich content that uses keywords appropriately and in context. To fix this problem, review your site for misused keywords. Typically, these will be lists or paragraphs of keywords, often randomly repeated. Check carefully, because keywords can often be in the form of hidden text, or they can be hidden in title tags or alt attributes. Once you've made your changes and are confident that your site no longer violates our webmaster guidelines, submit your site for reconsideration.