This bothers me to no end, so here is your internet grammar lesson for the day.
Main Entry:1there [](javascript:popWin(‘/cgi-bin/audio.pl?there001.wav=there’))Pronunciation: ˈther Function:adverb Etymology:Middle English, from Old English thǣr; akin to Old High German dār there, Old English thæt thatDate:before 12th century
1 : in or at that place <stand over there> —often used interjectionally
2 : to or into that place : thither <went there after church>
3 : at that point or stage <stop right there before you say something you’ll regret>
4 : in that matter, respect, or relation <there is where I disagree with you> 5 —used interjectionally to express satisfaction, approval, encouragement or sympathy, or defiance <there, it’s finished>
Main Entry:their [](javascript:popWin(‘/cgi-bin/audio.pl?their001.wav=their’))Pronunciation: thər, ˈther Function:adjective Etymology:Middle English, from their, pron., from Old Norse theirra, genitive plural demonstrative & personal pron.; akin to Old English thæt thatDate:13th century
1 : of or relating to them or themselves especially as possessors, agents, or objects of an action <their furniture> <their verses> <their being seen>
2 : his or her : his , her , its —used with an indefinite third person singular antecedent <anyone in their senses — W. H. Auden>