Tangent Communications saw its shares drop by 25% after it reported low sales during the Christmas period, exacerbated by "diseconomies of scale" hitting margins.The online printing and digital marketing group said it expected operating profit to halve from £2.4m in 2014 to £1.2m this year.Its Goodprint business suffered from a decrease in sales to £2.3m from £3.2m last year, while property agency Ravensworth has been impacted by a softer housing market and is expected to be uncertain during the next twelve months due to the general election.However, its printed.com platform is expected to grow by 20% to £7.6m. The group forecasts net cash to be of £1.4m and said it had carried out restructuring at its Newcastle site, adding a £0.7m non-recurring cost in the full year."We look to our online print business to fill capacity in the future but in the short term operating margins will remain lower," it said in a trading statement.Shares were down 25.13% to 3.65p on Wednesday at 14:18.