The Giorgio Chiellini rumour was the most daft recently. The logic seems to have been City have just hired an Italian, City need defenders, Juventus is a bit down because they are only in the Europa League so Chiellini will be coming to City. Quick round of articles are produced followed a few days later inevitably by the "news" that City have been unable to pick up the Italian International.
Here's what I wrote recently on Norfstander's excellent blog as part of his City Vox Pops feature
The club is being linked with players from all the top Italian teams but unless a player has had a specific falling out with their coach (as Inter's Cordoba is alleged to have done) or is looking for playing time with the World Cup approaching then I believe you can eliminate Milan, Inter and Fiorentina as they are in the Champions League last 16 and similarly while disappointing for the clubs to end up in the Europa League, Juventus and Roma.
So players from Sampdoria, Genoa, Lazio, Parma and Napoli make the most practical sense. For example the rumour that the club is interested in Sampdoria striker Giampaolo Pazzini (or Antonio Cassano) is one of the few that passes the smell test as it were, whilst Giorgio Chiellini with Juventus does not.
Unless you look at the context of the situation and by this I mean the player, the team he plays for, whether he is an international needing playing time in a World Cup year, whether the player has had a falling out with the manager, what competitions that club are still in and whether after all of that would he fit tactically at the new club, only then can you make a realistic evaluation as to the likelihood of a transfer.
99% of all the players that any Premier League team are connected with in the national press fail this test.
So lets look at Patrick Vieira. From a player standpoint the former Arsenal captain knows the the Premier League. He's older now, more experienced if you will and plays a position where you can age gracefully. He plays for Inter who are in the Champions League but he doesn't play regularly, appears to have fallen out of favour with Jose Mourinho and needs regular football to be in the French squad for South Africa 2010.
Tactically Mancini is said to prefer three midfielder enforcers and an attacking midfielder even if he has shown great flexibility with the current City squad in the first three games in charge. Vieira fits from a tactical standpoint.
Which means the bottom line is that the Patrick Vieira to City rumour passes the smell test. That is all. If such a move comes to pass, I look forward to seeing how this plays out further.
Use the criteria above when looking at the January transfer stories for any club. It really helps you cut down to the realistic targets.