Hey there,

I am really sorry for the delay of this reply,

You can override these following language string in Joomla language override page.

COM_EASYSOCIAL_STREAM_FILTER_TITLE_PLACEHOLDER="Set a filter title for your stream filter. Example: Sales, Marketing"

COM_EASYSOCIAL_STREAM_FILTER_HASHTAG_PLACEHOLDER="Set your hash tags. Example: #hr , #marketing , #sales"

Reference link : http://www.inmotionhosting.com/support/edu/joomla-3/languages/overrides

Hope this help.