Table 1. Basic statistics of the dataset, which is split into two periods: observation and testing.

About 13% of the tweets contain hashtags.

	Jan-Feb 2013 (Observation)	Mar 2013 (Testing)
# Tweets	2,449,711,388	1,339,702,599
# Tweets with hashtags	316,668,998	173,823,786
# Hashtags	27,923,499	16,802,087
# Users	92,356,790	72,963,020